A digestive enzyme functional only in infants is

Options

A. Lactase
B. Gastric lipase
C. Intestinal lipase
D. Chymosin

Answer

To solve the question "A digestive enzyme functional only in infants is," we will analyze the options provided and determine which enzyme is specifically functional during infancy.

### Step-by-Step Solution:

1. **Understanding the Options**: The options given are:
- A) Lactase
- B) Gastric lipase
- C) Intestinal lipase
- D) Chymosin

2. **Analyzing Lactase**:
- Lactase is an enzyme that breaks down lactose, the sugar found in milk, into glucose and galactose.
- It is present in both infants and adults, making it an incorrect option for this question.

3. **Analyzing Gastric Lipase**:
- Gastric lipase is an enzyme that helps in the digestion of fats in the stomach.
- This enzyme is also present in adults, so it cannot be the correct answer.

4. **Analyzing Intestinal Lipase**:
- Intestinal lipase functions in the small intestine to further digest fats.
- Like gastric lipase, this enzyme is present in adults as well, thus it is not the correct choice.

5. **Analyzing Chymosin**:
- Chymosin, also known as rennin, is an enzyme that helps coagulate milk, which is particularly important for infants as it aids in the digestion of milk.
- This enzyme is predominantly found in infants and is not active in adults, making it the correct answer.

6. **Conclusion**:
- Based on the analysis, the enzyme that is functional only in infants is **Chymosin** (Option D).

### Final Answer:
**Chymosin**